APPARATUS FOR PROJECTING WIRE

Abstract

An apparatus (100) for projecting a stay wire (7) across a plurality of line wires (2) in a fence mesh forming machine. The apparatus (100) has at least two rollers (109) defining a wire travel path (W) between the rollers and arranged to contact the wire (7) and move the wire along the wire travel path (W) upon rotation of the rollers (109). At least one of the rollers (109) is arranged to be directly driven by a respective motor (115). Preferably, each of the rollers (109) is arranged to be directly driven by a respective motor (115).

Description

FIELD OF INVENTION

This invention relates to an apparatus for projecting a stay wire across a plurality of line wires in a fence mesh forming machine.

BACKGROUND OF THE INVENTION

Forms of fence mesh are known in which the wires forming the fence are knotted together at each or many wire intersections. In general, knotted fence mesh is stronger than wire fence in which the fence wires are not knotted together at their intersections and which is typically used in domestic or light industrial applications. Knotted fence mesh is used for applications where additional strength is required, such as for containing larger or stronger animals such as horses or deer for example.

Knotted fence mesh with a rectangular or square mesh for example is typically formed from a number of generally parallel line wires, which will extend generally horizontally when the fence mesh is set in position between fence posts, and lengths of stay wire which extend laterally across the line wires at regular spacings (and generally vertically when the fence mesh is set in position).

In machines for forming knotted fence mesh a number of continuous line wires are fed to a bed of the machine comprising a number of similar knot boxes, and stay wire is fed into the machine bed across the line wires. Such machines typically have a step-wise operation and form a series of knots along a length of stay wire at each intersection of the stay wire and the line wires at each operational step or “beat” of the machine. At each step or beat the line wires are advanced forward in parallel through the side by side knot boxes of the machine bed, stay wire is fed into the bed of the machine across the line wires at the knot boxes, at approximately 90 degrees to the line wires in the case of a machine for forming rectangular fence mesh, a length of stay wire is cut, and simultaneously at each knot box at an intersection between the line wires and the stay wire a knot securing the stay wire to the line wire is formed.

A fence mesh forming machine is described in U.S. Pat. No. 6,668,869. That fence mesh machine is shown generally in FIGS. 1a and 1b.

FIG. 1 a shows a number of continuous line wires 2 and knot wires 3 being fed to a bed 4 of the machine 1, which bed has a plurality of side by side knot boxes 5. The line wires 2 enter the machine at its base, are turned through 90 degrees around rollers 6 and pass vertically through the knot boxes 5. One line wire 2 and one knot wire 3 pass through each knot box 5 with different orientations. A continuous stay wire 7 is projected across the bed of the machine via a stay wire feed apparatus comprising two aligned pairs of driven rollers 8 and a free-running guide sheave 8a so as to transversely cross each of the knot boxes 5, thereby forming a plurality of stay wire-line wire intersections.

The machine 1 has a main drive roller 9 which pulls the completed fence mesh through the knot boxes 5, the drive roller being driven by an electric motor 10. The completed fence mesh (indicated generally by reference numeral 11 in FIG. 1b) then extends around a further roller 12, and would typically extend to a coiling machine or take-up unit (not shown) to form it into a coil for ease of handling and transportation.

The knotted fence mesh forming machine 1 generally has a step-wise operation and forms a series of knots along the length of stay wire 7 at each line wire-stay wire intersection at each step or “beat” of the machine. At each step or beat the line wires 2 are advanced forward in parallel through the side by side knot boxes 5 in the machine bed 4 via the drive roller 9, a stay wire 7 is fed into the bed 4 of the machine across the line wires at the knot boxes 5, at 90° for forming square fence mesh as shown, a length of the stay wire 7 is cut, and simultaneously in each knot box 5 at each intersection between the line wires and the stay wire a knot securing the stay wire to the line wire is formed.

FIG. 1 c shows the drive mechanism of the stay wire feed apparatus of the system of FIGS. 1a and 1b. Each roller 8, 8′ is mounted on a respective elongate shaft 8a, 8a′, each of which carries a gear 8b, 8b′. The upper gears 8b mesh with the lower gears 8b′, and the lower gears 8b′, mesh with a drive gear 8c on a drive shaft 8d. The rollers are driven by a single relatively large drive motor (not shown), and motive force is transferred from the motor via drive shaft 8d and gear 8c, to the lower gears 8b′. The motive force is transmitted from the lower gears 8b′ to the upper gears 8b, from the lower gears 8b′ to the lower rollers 8′ via the respective lower shafts 8a′, and from the upper gears 8b to the upper rollers 8 via the respective upper shafts 8a. This indirect drive of the relatively large rollers, via a single large motor, multiple shafts, and multiple gears, adds significantly to the inertia of the system that projects the stay wire across the bed of the machine. Due to that inertia, the response time of the stay wire feed apparatus is reasonably slow. The configuration shown in FIG. 1c requires about 230 milliseconds to project the stay wire across the bed of the machine.

As the machine has a step-wise operation, it will be appreciated that a “bottle-neck” in any step of the machine will have a significant overall effect on the speed and overall efficiency of the machine. Accordingly, it is desirable to minimise the duration of each step.

Apparatuses for working or forming wire are described in U.S. Pat. No. 6,502,446; U.S. Pat. No. 6,490,901; U.S. Pat. No. 5,566,564; and JP 4-319012. Apparatuses for feeding wire short distances in welding machines are described in U.S. Pat. No. 3,672,655 and JP 55-57381.

It is an object of at least preferred embodiments of the present invention to provide an apparatus for projecting wire which offers faster operation than the apparatus described with reference to FIG. 1c above, or which will at least provide the public with a useful choice.

SUMMARY OF THE INVENTION

The term “comprising” as used in this specification and claims means “consisting at least in part of”; that is to say when interpreting statements in this specification and claims which include “comprising”, the features prefaced by this term in each statement all need to be present but other features can also be present. Related terms such as “comprise” and “comprised” are to be interpreted in similar manner.

In accordance with a first aspect of the present invention, there is provided an apparatus for projecting a stay wire across a plurality of line wires in a fence mesh forming machine, the apparatus comprising at least two rollers defining a wire travel path between the rollers and arranged to contact the wire and move the wire along the wire travel path upon rotation of the rollers, wherein at least one of the rollers is arranged to be directly driven by a respective motor.

Suitably, the or each motor comprises a housing with a drive shaft extending from the housing, and a roller is mounted on the drive shaft of the or each motor.

Advantageously, each roller comprises a generally arcuate contact surface extending about its perimeter for receipt of, and contact with, part of the wire to be projected.

The rollers may be biased towards the wire travel path, to assist in maintaining contact between the rollers and a wire as it is being moved through the wire travel path. The apparatus preferably comprises a compression spring arranged to push against a member associated with each roller to bias the rollers towards the wire travel path. The bias of each roller is advantageously adjustable. An adjuster may be associated with each spring, and configured such that moving the adjuster alters the amount of spring force which biases each roller.

Preferably, the or each motor is an electric servo motor.

The apparatus advantageously comprises three rollers defining the wire travel path and arranged generally annularly about the wire travel path to contact the wire and move the wire along the wire travel path upon rotation of the rollers. The rollers may be arranged at angles of about 120 degrees about the wire travel path.

The apparatus may comprise more than three rollers arranged generally annularly around the wire travel path.

Preferably, each roller is arranged to be directly driven by a respective motor.

In accordance with a second aspect of the present invention, there is provided an apparatus for projecting a stay wire across a plurality of line wires in a fence mesh forming machine, the apparatus comprising three rollers defining a wire travel path and arranged generally annularly about the wire travel path to contact the wire and move the wire along the wire travel path upon rotation of the rollers, wherein each of the rollers is arranged to be directly driven by a respective motor.

In accordance with a third aspect of the present invention, there is provided a fence mesh forming machine comprising: a machine bed arranged to pass a plurality of substantially parallel line wires therethrough; and an apparatus as outlined in the first aspect above configured to project a stay wire a plurality of line wires.

Suitably, the apparatus is configured to rotate the rollers for a predetermined time period and at a predetermined speed, to project the stay wire a predetermined distance.

The apparatus may be configured to project the stay wire across all of the line wires in the plurality of line wires.

In accordance with a fourth aspect of the present invention, there is provided a method of projecting a stay wire across a plurality of line wires in a fence mesh forming machine comprising a machine bed arranged to pass a plurality of substantially parallel line wires therethrough and an apparatus as outlined in the first aspect above, the method comprising feeding a stay wire between the rollers of the apparatus, and operating the apparatus to project the stay wire across a plurality of line wires.

The method may comprise rotating the rollers for a predetermined time period and at a predetermined speed, to project the stay wire a predetermined distance.

The method may comprise projecting the stay wire across all of the line wires in the plurality of line wires.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention are described by way of example only, with reference to the accompanying drawings in which:

FIGS. 1 a and 1b are perspective views of an existing knotted fence mesh forming machine, which includes an existing apparatus for projecting the stay wire across the bed of the machine;

FIG. 1 c is a perspective view of the drive mechanism of the existing apparatus for projecting stay wire of the machine of FIGS. 1a and 1b;

FIG. 2 schematically shows part of a typical fence mesh formed by a machine such as that shown in FIGS. 1a to 1c;

FIG. 3 is a front perspective view of an apparatus for projecting wire in accordance with a preferred embodiment of the present invention;

FIG. 4 is a schematic end view of the apparatus of FIG. 3 showing an advantageous orientation of the rollers;

FIG. 5 is a cutaway perspective view of the apparatus of FIG. 3;

FIG. 6 is a detail view showing part of the apparatus of FIG. 3; and

FIG. 7 is a schematic part-section view of a roller and motor of the apparatus of FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention has application in a knotted fence mesh forming machine such as that shown in FIGS. 1a and 1b. The general operation of that machine is described in U.S. Pat. No. 6,668,869, and will not be described in detail again here. The content of U.S. Pat. No. 6,668,869 is incorporated herein in its entirety by way of reference.

FIG. 2 shows the travel of wires through a fence mesh forming machine, such as that shown in FIG. 1. The line wires 2 travel in a generally parallel arrangement in a direction indicated by arrow L. After the line wires have travelled a predetermined distance, a stay wire 7 is fed across the line wires in the direction indicated by arrow S. A stay wire placer assembly may then locate and grip the stay wire. The stay wire would then be cut to a desired length, and knots indicated by X would be formed at all or a majority of the line wire-stay wire intersections. Generally, at each side of the fence mesh, the stay wire would be twisted around the line wire rather than being connected thereto by a knot.

A preferred embodiment apparatus for projecting a stay wire across the line wires is shown in FIG. 3 and is indicated generally by reference number 100. In the machine of FIGS. 1a and 1b, the apparatus of FIG. 1c could be replaced by the preferred embodiment apparatus 100.

The apparatus 100 includes a base plate 101 which in the embodiment shown supports three feed arrangements 103. Each feed arrangement includes an arm 105 that defines a roller housing and that is preferably pivotally mounted relative to the base plate 101 via respective pivots 107 (see FIGS. 5 and 6). Mounted for rotation to each arm is a roller 109. Each roller has an axis of rotation 109a which, as shown, may lie substantially parallel to the pivot axis. A wire travel path is formed between the rollers 109 to feed the wire. As can be seen in FIG. 7, each roller preferably comprises a hub 109c that is received in bearings 121 in the housing 105.

An advantageous arrangement of the rollers 109 relative to a wire travel path for a stay wire 7 is shown in FIG. 4. The rollers 109 are arranged generally annularly, i.e. radially, around the wire travel path W to contact the wire 7 travelling therethrough from different sides/angles. The rollers are preferably arranged with substantially equal angular spacing around the wire travel path W, so in the embodiment shown the rollers are preferably arranged at about a 120 degree angular spacing. If four rollers are used, the rollers would preferably be arranged with about a 90 degree angular spacing. Five rollers would preferably be arranged with about a 72 degree angular spacing.

Each roller preferably has an arcuate contact surface 109b formed in its perimeter to receive and contact part of the wire 7 to be fed through the wire travel path W. This assists in maintaining the wire in the correct alignment/position as it travels through the wire travel path.

The rollers are preferably arranged with substantially coplanar axes of rotation, although that is not essential.

It is preferred that the rollers 109 are biased towards the wire travel path W as indicated by arrows B in FIG. 4. To achieve that, a biasing device which may be a compression spring 111 for example acts against a part of each support arm 105 distal the pivot 107 and roller 109. The spring biases that part of the support arm away from the base plate and thereby the roller 109 towards the wire travel path W. The rollers 109 are thereby biased towards one another, to assist in maintaining contact between the contact surfaces 109b of the rollers and a wire 107 being fed through the wire travel path W by movement of the rollers. That also assists in compensating for any discrepancies in cross-section of the wire which may result from manufacturing variations.

In a preferred embodiment, the biasing force of each roller is preferably adjustable. In the embodiment shown, adjustment of the biasing force acting on the rollers is achieved by rotating an adjuster 113 associated with each roller, which alters the compression and thereby the biasing force of the spring 111 which biases the roller. The same biasing arrangement will preferably be provided for each roller.

Other biasing arrangements could be used if desired.

In the embodiment shown, a drive motor indicated generally by reference numeral 115 is associated with each roller and is operable to rotate that roller. The rollers 109 are arranged to be directly driven by the respective motors 115. That is, the output of each motor is transferred to the respective roller without gears or additional shafts. FIG. 7 schematically shows a part-cross section view of the motor and the roller. As can be seen, the motor comprises a housing 115a and a drive shaft 115b extending from the housing, and the roller is mounted on the drive shaft of the motor. A key (not shown) will generally be used to key the roller to the drive shaft. Preferably, the roller is directly mounted on the drive shaft as shown without an intervening bush or similar item, to minimise inertia.

The motors 115 are preferably synchronised such that rotation of the rollers is synchronised. As the motors are operated, the rollers rotate and thereby move a wire 7 through the wire travel path via contact between the arcuate contact surfaces of the rollers and the wire 7. The motors are preferably electric servo motors.

The wire is preferably directed out of the apparatus through a feed out nozzle 117 as shown in FIG. 3, which is suitably substantially cylindrical in configuration as shown. As shown in FIG. 5, a further guide 119 which would generally be coaxial with the feed out nozzle 117 may be provided to assist in aligning the wire 7 with the wire travel path W between the rollers.

In operation of the machine, the plurality of line wires 2 will be fed a predetermined distance through the machine bed. Once the predetermined distance has been reached, movement of the line wires 2 is stopped and the motors 115 of the preferred embodiment apparatus 100 are operated to cause the rollers 109 to co-rotate. That causes the stay wire 7 to be fed through the wire travel path as a result of frictional engagement with the contact surfaces 109b of the rollers. The speed of rotation of the rollers will be sufficient that the stay wire 7 will pass through the feed out nozzle 117 and will be projected across the plurality of line wires.

To project the stay wire the required distance, the rollers may be rotated for a predetermined time at a predetermined speed, which can be achieved by operating the motors at a suitable speed for a suitable period of time. Alternatively, or in addition, one or more sensors could be used to determine when the stay wire has been projected the desired distance (such as by determining when a sufficient length of stay wire has been fed from the preferred apparatus), at which point operation of the motors 115 will cease to stop the feeding out of stay wire.

The stay wire may then be gripped by a placer assembly (not shown) and cut to length by a cutting mechanism (not shown), and knots X will be formed at least a majority of the line wire-stay wire intersections. The ends of the stay wires would generally be twisted around the outer line wires.

Following that, the line wires will again be moved a predetermined distance, and the process will be repeated.

The above describes preferred embodiments, and modifications may be made thereto without departing from the scope of the following claims.

For example, in the embodiment shown and described, each roller is arranged to be directly driven by a respective motor. In some embodiments, it is not necessary that all rollers are driven, and one or more of the rollers could be an idler which rotates as a result of movement of the wire through the wire travel path. However, it is preferred for optimal performance that each roller is directly driven by a respective motor.

The preferred embodiment is described above with reference to projecting stay wires in a knotted fence mesh forming machine. However, it will be appreciated that the preferred embodiment has applications for projecting or feeding other types of wires in other types of machines.

The motors 115 are described as electric servo motors. Different types of motors could be used, such as hydraulic motors. However, electric servo motors are preferred as they have low inertia and fast response times.

Further, the rollers are shown as being generally disk-shaped. However, it will be appreciated that while that is the preferred embodiment, the rollers could be other shapes such as generally cylindrical for example.

In the embodiment shown, the stay wire is projected across all of the line wires in the machine. For some applications, it may be desirable that the stay wire is only projected across some of the line wires.

Additionally, the preferred embodiment is described as having three rollers, however it will be appreciated that four or more rollers could be used for example, with the four rollers arranged generally annularly around the wire travel path. In such an embodiment, it may be necessary to offset the axes of some of the rollers somewhat so that they can fit around the wire travel path. In an alternative embodiment, only two rollers may be provided which define the wire travel path between the rollers.

By providing independent direct drive of roller(s) by respective motor(s), the inertia of the apparatus is reduced over the apparatus shown in FIG. 1c, due to the elimination of additional gears, shafts, etc. The result is that the speed of projecting the stay wire is improved over the apparatus of FIG. 1c.

Additional speed improvements are obtained in the preferred embodiment by using three or more rollers arranged generally annularly around the wire travel path, each of which is directly driven by a respective motor. That is because the rollers and motors can be smaller and thereby have less inertia than in the apparatus of FIG. 1c. The preferred embodiment apparatus can project the stay wire across the bed of the fence mesh forming machine shown in FIGS. 1a and 1b in about 90 milliseconds. By using the preferred embodiment apparatus, overall productivity of the machine of FIGS. 1a and 1b can be improved by about 16%.

Claims

1. An apparatus for protecting a stay wire across a plurality of line wires in a fence mesh forming machine, the apparatus comprising three rollers defining a wire travel path and arranged generally annularly about the wire travel path to contact the wire and move the wire along the wire travel path upon rotation of the rollers, wherein each of the rollers is arranged to be directly driven by a respective motor.

2. An apparatus as claimed in claim 1, wherein each motor comprises a housing with a dirve shaft extending from the housing, and wherein a rolelr is mounted on the dirve shaft of each motor.

3. An apparatus as claimed in claim 1, wherein each roller comprises a generally arcuate contact surface extending about its perimeter for receipt of, and contact with, part of the wire to be projected.

4. An apparatus as claimed in claim 1, wherein the rollers are biased towards the wire travel path, to assist in maintaining contact between the rollers and a wire as it is being moved through the wire travel path.

5. An apparatus as claimed in claim 4, comprising a compresssion spring arranged to push against a member associated with each roller to bias the rollers towards the wire travel path.

6. An apparatus as claimed in claim 5, wherein the bias of each roller is adjustable.

7. An apparatus as claimed in claim 6, wherein an adjuster is associated with each spring, and is configured such that moving the adjuster alters the amount of spring force which biases each roller.

8. An apparatus as claimed in claim 1, wherein each motor is an electric servo motor.

9. An apparatus as claimed in claim 1, wherein the rollers are arranged at angles of about 120 degrees about the wire travel path.

10. An apparatus as claimed in claim 1, comprising more than three rollers arranged generally annularly around the wire travel path.

11. A fence mesh forming machine comprising: a machine bed arranged to pass a plurality of substantially parallel line wires therethrough; andan apparatus in accordance with claim 1 configured to project a stay wire a plurality of line wires.

12. A fence mesh forming machine as claimed in claim 11, wherein the apparatus is configured to rotate the rollers for a predetermined time period and at a predetermined speed, to project the stay wire a predetermined distance.

13. A fence mesh forming machine as claimed in claim 11, wherein the apparatus is configured to project the stay wire across all of the line wires in the plnrality of line wires.

14. A method of projecting a stay wire across a plurality of line wires in a fence mesh forming machine comprising a machine bed arranged to pass a plurality of substantially parallel line wires therethrough and an apparatus as claimed in claim 1, the method comprising feeding a stay wire between the rollers of the apparatus, and operating the apparatus to project the stay wire across a plurality of line wires.

15. A method as clailmied in claim 14, comprising rotaiting the rollers for a predetermined time period and at a predetermined speed, to project the stay wire a predetermined distance.

16. A method as claimed in claim 15, comprising protecting the stay wire across all of the line wires in the plurality of line wires.